Why does outlook hang waiting for javascript to run in Edge?

I have had OWA for office365 hanging a lot on MS Edge/linux past week or so(after over a year of no issues, I use Edge for OWA just thinking it may be better supported than firefox, also so that I am not logged into a MS account with my main firefox browser), I don't use the PWA, though I do use the PWA for Teams/Linux(no issues there). I have had OK luck so far deleting the office365 cookies and killing the tab and reloading and it seems to work for a while, until it hangs again (most recently seems to hang overnight, my computer is on 24/7).

Currently on Mint 20 (based on Ubuntu 20) with MS Edge Version 121.0.2277.83 (Official build) (64-bit)

(update)

Upgraded recently to MS Edge 121.0.2277.106 (Official build) (64-bit) and the problem persists there. At first I thought it appeared to be fixed but just now saw OWA was hung overnight. closing the tab, clearing the cookies for office.com and opening a new tab for OWA worked fine. Though I have seen this particular work around NOT work for me recently on a couple of occasions it could of been a timing issue, for example noticing that it is hung, then hitting refresh, then closing the tab and closing cookies and trying again, I think didn't work perhaps a thread or something was still hanging on to something. But if it's been dead for a while, and I don't try to force refresh, just close the tab, clear cookies and open a new tab I think that seems to be somewhat reliable . Just have to try to remind myself to do that method to recover.

(update 4/17/24)

Whatever is happening seemed to get significantly worse over the past 24 hours or so, OWA (in Edge browser not the PWA) goes unresponsive within seconds after even restarting Edge, totally unusable now. I tried upgrading to the latest edge stable as of a short time ago this morning running Version 123.0.2420.97 (Official build) (64-bit), however there is no change in behavior. I have switched back to Firefox for this use case (was only really using edge for Office 365 related things in part for workload isolation and also assumed it would be most compatible).

(update 5/15/24)

Stating the obvious of course but just to be clear, zero issues with OWA in Firefox ESR/Linux since I switched on 4/17/24 away from edge. I still use Edge PWA for Teams, and for some other things(like writing this comment since I am already logged into the MS account). No other web sites/pages hang on Edge on Linux in my experience like Outlook did. I haven't tried Outlook on Edge/Linux since seems like whatever issues are there remain unresolved based on other comments.

It seems hit or miss for me whether the problem triggers or not.

Due to hit/miss nature of it, and the fact that completely purging cache/etc. and still hitting the issue says to me it's a product problem.

One of my co-workers let me know they hit the same thing with Chrome - others in this thread have said as much as well.

My speculation: some kind of a/b test targeting webkit-based browsers that has gone awry.

I think it's something in Outlook's web, too. I use Fedora 39 with MS Edge 122.0.2365.52 (stable release) and open my Outlook email in a new tab (not PWA), however after some seconds of loading, the page just hangs and stops responding to clicks. This issue only happens in Outlook page, not in others. Even in a couple of times after loading, I've seen an error message in outlook page "Fatal signal 7 (SIGBUS)". Problem persists 'til now.

Have you had any luck? I'm experiencing the same issue on Ubuntu 22.04. I have tried Outlook PWA's with both Chrome and Edge. For the first couple days they work well, then once the first crash happens it will continue to happen over and over again shortly after launch, just as you describe. I don't think it's an Edge-specific issue, but a Chromium one as I've experienced identical behavior in Chrome and Edge.

Really wishing Firefox supported PWA's right about now...

Good to know that it's not just a PWA problem. My current fix is just to kill the process, delete ~/.cache/microsoft-edge/, and re-launch. I don't use Edge for anything except for outlook so that has no adverse affects for me.